Correction of refractive errors using contact lenses is well known. Conventional contact lenses provide correction for low order optical aberrations, such as defocus and astigmatism, leaving higher order aberrations uncorrected. Recently, contact lenses for correction of higher order aberrations, such as third order coma and spherical aberrations, and irregular astigmatism have been disclosed as well. These lenses are disadvantageous in that their design and fitting does not take into account both the cortical influences, meaning the neuro-adaptive influences of the individual's visual cortex on vision, and the changes associated with spherical aberrations, particularly those spherical aberration changes associated with aging. Thus, the known corrections for spherical aberration and other high order aberrations have been problematic because of the multiple variables and optical challenges associated with correcting these aberrations in humans.
For example, one such type of correction, aspheric contact lenses, are known to reduce by as much as 40 to 60% of spherical aberrations, which are the most common and disabling of the high order aberrations for human vision. The reason that not a greater percentage of spherical aberrations are corrected by aspheric contact lenses is that the conventional aspheric contact lenses and methods of fitting such lenses address only lower order visual acuity, or the quantitative vision of an individual. This ignores neuro-adaptive effects.